 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal;

 import java.util.HashMap ;
 import java.util.Iterator ;

 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.ui.IActionFilter;
 import org.eclipse.ui.internal.util.Util;

 /**
  * An ObjectFilterTest is used to read an object filter from XML,
  * and evaluate the results for a given object.
  */
 public class ObjectFilterTest {
     private HashMap filterElements;

     /**
      * Create a new object filter.
      */
     public ObjectFilterTest() {
         // do nothing
 }

     /**
      * Add a filter element to the test. This element must contain
      * a name value filter pair, as defined by the
      * <code>org.eclipse.ui.actionFilters</code> extension point.
      */
     public boolean addFilterElement(IConfigurationElement element) {
         String name = element.getAttribute("name");//$NON-NLS-1$
 if (name == null) {
             return false;
         }

         // Get positive property.
 String value = element.getAttribute("value");//$NON-NLS-1$
 if (value == null) {
             return false;
         }
         if (filterElements == null) {
             filterElements = new HashMap ();
         }
         filterElements.put(name, value);
         return true;
     }

     /**
      * Returns whether the object filter correctly matches a
      * given object. The results will be <code>true</code> if there is
      * a filter match.
      * <p>
      * If <code>adaptable is true</code>, the result will also be
      * <code>rue</code> if the object is a wrapper for a resource, and
      * the resource produces a filter match.
      * </p>
      *
      * @param object the object to examine
      * @returns <code>true</code> if there is a filter match.
      */
     public boolean matches(Object object, boolean adaptable) {
         // Optimize it.
 if (filterElements == null) {
             return true;
         }

         // Try out the object.
 if (this.preciselyMatches(object)) {
             return true;
         }
         return false;
     }

     /**
      * Returns whether the object filter correctly matches a given object.
      */
     private boolean preciselyMatches(Object object) {
         // Get the action filter.
 IActionFilter filter = (IActionFilter)Util.getAdapter(object, IActionFilter.class);
         if (filter == null) {
             return false;
         }

         // Run the action filter.
 Iterator iter = filterElements.keySet().iterator();
         while (iter.hasNext()) {
             String name = (String ) iter.next();
             String value = (String ) filterElements.get(name);
             if (!filter.testAttribute(object, name, value)) {
                 return false;
             }
         }
         return true;
     }
 }


